handbook of modern sensors

404 Humidity and Moisture Sensors
Fig. 13.10. Oscillating humidity sensor.
shift controls current through the Peltier cooler, thus changing the temperature of
the quartz crystal to stabilize at the dew point temperature. The major difficulty in
designing the piezoelectric hygrometer is in providing an adequate thermal coupling
between the cooler and the crystal while maintaining small size of the crystal at a
minimum mechanical loading [16]. Naturally, this method may be employed by using
the surface acoustic-wave (SAW) sensors, similar to that of Fig. 12.8 of Chapter 12,
where the stimulus place is the area subjected to the sampled gas.
References
1. Quinn, F. C. The most common problem of moisture/humidity measurement
and control. In: Moisture and Humidity, Proceedings of the 1985 International
Symposium on Moisture and Humidity. Chaddock, J. B. ed., ISA, Washington,
DC, 1985, pp. 1–5.
2. Carter, E. F., ed. Dictionary of Inventions and Discoveries. Crane, Russak and
Co., New York, 1966.
3. Baughman E. H. and Mayes, D. NIR applications to process analysis. Am. Lab.,
21(10), 54–58, 1989.
4. Berry, F. A., Jr. Handbook of Meteorology. McGraw-Hill, New York, 1945, p.
343.
5. Conditioner Circuit, Appl. Handbook, Linear Technology, Inc., Milpitas, 1990.
6. Sashida, T. and Sakaino, Y. An interchangeable humidity sensor for an industrial
hygrometer. In: Moisture and Humidity. Proceedings of the International
Symposium on Moisture and Humidity. Chaddock, J. B. ed., Washington, DC,
1985.
7. Carr-Brion, K. Moisture Sensors in Process Control. Elsevier Applied Science,
New York, 1986.
8. Jachowicz, R. S. and Dumania, P. Evaluation of thin-film humidity sensor type
MCP–MOS. In: Moisture and Humidity. Proceedings of the International Symposium
on Moisture and Humidity. Chaddock, J. B. ed., ISA, Washington, DC,
1985.